Hades Nebula is set in 2124: humanity needs to find new planets to settle on because energy reserves grow thin. So they send ten ships to different places in the universe to find something suitable. Unfortunately the emperor Hades gets his hands on the plans and wants to seize the colony ships. The computer of Colony 7 has a malfunction, however, meaning they arrive two years early. This gives them the time to prepare an attack on Hades Nebula, Hades' headquarter.
The player takes a role of a small space ship to destroy Hades and his evil minions. The game is a vertically scrolling shooter in which the player spends most of the time with dodging enemies, their bullets or asteroids. Of course he also has the weapon to shoot back. During the course of the game he can pick up extras which grant advantages like better speed or attack power.